Pulmonary arterial hypertension is a vasculoproliferative disorder of the small pulmonary arteries, which is characterized by vasoconstriction and proliferation of the vascular cells in the pulmonary vessel wall. During the last decade, therapeutic options for the treatment of this life-threatening disease have significantly improved. Drugs like prostacyclin, endothelin receptor antagonists and phosphodiesterase 5 inhibitors, which mainly address the increased vascular tone, have been approved for the treatment of pulmonary arterial hypertension and represent the current therapeutic options. The development of a causal treatment targeted on the key events in disease progression (e.g. increased proliferation, migration and resistance to apoptosis of pulmonary vascular cells) aiming a normalization of the pulmonary artery wall structure is the current focus of research. Therefore new non-vasoactive drugs with anti-proliferative properties are investigated, which can not only attenuate (anti-remodeling) but reverse (reverse-remodeling) the disease. These compound classes include growth factor receptor inhibitors (e.g. tyrosine kinase inhibitors), statins, serotonin receptor antagonists and Rho-kinase inhibitors. Preclinical investigations and clinical trials for some of these substances were already initiated addressing safety and efficacy. In summary, further insight into the pathology of pulmonary arterial hypertension is needed to further advance drug development and treatments to improve the management of patients.